Preparation of polymers of conjugated dienes using organolithium/polar compound catalyst systems



'No Drawing.

United States Patent M 3,301,840 PREPARATION OF POLYMERS OF CONJUGATED DIENES USING ORGANOLITHIUM/ POLAR COM- 4 POUND CATALYST SYSTEMS Robert P. Zelinski, Bartlesville, Okla., assignor to Phillips Petroleum Company, a corporation of Delaware Continuation of application Ser. No. 718,484, Mar. 3, 1958. This application Sept. 17, 1964, Ser. No. 397,271

19 Claims. (Cl. 260-942) This application is a continuation of copending application Serial No. 718,484 filed March 3, 1958, now abandoned.

This invention relates to a method for polymerizing conjugated dienes. In one aspect, the invention relates to a method for controlling the ratio of cis to vinyl linkages in conjugated diene polymers.

Recently, considerable interest has been-shown in the development of specific catalyst systems which are capable of producing polymers having a desired configuration. The term sterospecific catalyst has been used to describe such catalyst systems. It has been known for a number of years that n-butyllithium can be used as a catalyst in the polymerization of a conjugated diene, such as 1,3-butadiene. When butadiene is polymerized in a hydrocarbon solvent in the presence of n-butyllithium, approximately 80 to 85 percent or more of the polymer is formed by 1,4-addition of the monomer unit. A greater proportion of the 1,4-linkages are of the trans type rather than of the cis type.

It is an object of this invention to provide a novel process for polymerizing conjugated dienes to rubbery polymers of controlled cis-vinyl linkage ratios.

Another object of the invention is to provide a process for polymerizing conjugated dienes to rubbery polymers at an increased reaction rate.

A further object of the invention is to provide a process for preparing a novel block polymer.

Other and further objects and advantages of the invention will become apparent to those skilled in the art upon consideration of the accompanying disclosure.

The instant invention resides in the discovery of a process whereby conjugated dienes can be polymerized to rubbery polymers of a desired cis-vinyl ratio. Broadly speaking, the process comprises contacting a conjugated diene with an organolithium compound in the presence of a solvent mixture comprising a hydrocarbon selected from the group consisting of aromatic, paraflinic andcycloparafiinic hydrocarbonsand a polar compound. In general, the polar compound used in the solvent mixture is one which does not inactivate the organolithium compound. It has been found that by adjusting the amount of the polar compound contained in the solvent mixture, it is possible to obtain a diene polymer having a desired ratio of cis 1,4-linkages to vinyl linkages (1,2). It has also been discovered that by carrying out the polymerization in the presence of a multi-component solvent mixture in which one of the components is a polar compound, the reaction rate of the organolithium catalyzed polymerization is greatly increased.

The instant invention in one aspect is also concerned with the production of novel block polymers of conjugated dienes. In accordance 'With this embodiment, the process includes the steps of initially contacting a conjugated diene with an organolithium compound in the presence of a'hydrocarbon solvent, and thereafter, while the polymerization is still proceeding, adding a polar com- 3,301,840 Patented Jan. 31, 1967 than percent conversion in the presence of a hydrocarbon solvent only, a polymer block is formed in which the cis-trans-vinyl ratio is about 40-50-10. 7 A polar compound, such as 1,2-dimethoxyethane, is then added to the reaction mixture, and the polymerization is allowed to proceed. A polymer blockhaving a cis-trans-vinyl ratio of about 10-10-80 is thereby formed onto the end of the first-formed polymer block.

The monomeric material polymerized to produce rubbery polymers by the process of this invention comprises conjugated diene containing from 4 to 10, inclusive, carbon atoms. Examples of conjugated dienes which can be used include 1,3-butadiene, 2-methyl-1,3-butadiene (isoprene), 2,3 dimethyl 1,3-butadiene, 2-methyl-l,3- pentadiene, 2,3 dimethyl 1,3-pentadiene, 2-methyl-3- pentadiene, Z-phenylbutadiene, and the like. It is to be understood that mixtures of the aforementioned conjugated dienes can be polymerized in accordance with the process of this invention.

As mentioned hereinabove, the polymerization is carried out in the presence of a solvent mixture comprising a hydrocarbon selected from the group consisting of aromatic, parafiinic and cycloparaflinic hydrocarbons anda polar solvent which does not inactivate the organolithium compound utilized as the catalyst. The solvent mixture is one which is liquid and inert under conditions of the process. Examples of suitable aromatic hydrocarbons, paraffins and cycloparafiins which can be used as-one of the components of the two-component solvent mixture include benzene, toluene, xylene, ethylbenzene, isobutane, n-pentane, isooctane, n-decane, cyclopentane, methylcyclopentane, dimethylcyclopentane, ethylcyclopentane, cyclohexane, methylcyclohexane, dimethylcyclohexane, and the like. Mixtures of these solvents can also be employed. Examples of polar compounds which do not inactivate the organolithium catalyst and which may, therefore, be utilized as the second component of the solvent mixture are ethers, thioethers (sulfides), and tertiary amines. Specific examples of such polar materials include dimethyl ether, diethyl ether, ethyl methyl ether, ethyl propyl ether, di-n-propyl ether, di-n-octyl ether, divinyl ether,

tetramethylene oxide (tetrahydrofuran), 1,2-dimethoxyethane, dioxane, paraldehyde, anisole, dibenzyl ether, di phenyl ether, dimethyl sulfide, diethyl sulfide, di-n-propyl sulfide, di-ri-butyl sulfide, dimethylethylamine, tri-n-propylamine, tri-n-butylamine, trimethylamine, triethylamine, N,N-dimethylaniline, N-ethylpiperidine, N-methyl-N-ethylaniline, N-methylmorpholine, and the like. It is to be understood that mixtures of these polar compounds can also be employed in the practice of the instant invention.

The amount of polar compound contained in the twocomponent solvent mixture is in the range of 0.005 to 50 weight percent of the total solvent mixture. The re mainder ot' the solvent mixture is a paraflinic, cycloparaffinic or aromatic hydrocarbon as described hereina-bove. It has been found that very small amounts of the polar compounds, e.g., as little as one weight percent or less, have an effect on the ratio of cis-1,4 linkages to vinyl linkages in the conjugated diene polymer. In general, it can be stated that the more active polar compounds, such as tetrahydrofuran and 1,2-dimethoxyethane, exert an effeet on the polymer configuration when present at less than the molar concentrations of the alkyllithium. In the case of the less active polar materials, they must be present in excess of the molar concentrations of alkyllithiuin before a change in polymer structure can be detected.

The organolithium compound used as the catalyst in the practice of the process of this invention corresponds to the general formula RLi, wherein R is selected from the group consisting of alkyl, aryl, cycloalkyl, aralkyl, alkaryl, alkylcycloalkyl and cycoalkylalkyl radicals. The R group preferably contains from 1 to 10, inclusive, carbon atoms. Examples of organolithium compounds which can be used include methyllithium, isopropyllithium, nbutyllithium, tert-octyllithium, n-decyllithium, phenyllithium, naphthyllithium, 4-butylphenyllithium, p-tolyllithium, 4-phenylbutyllithium, cyclohexyllithium, -4-butylcyclohexyllithium, 4-cyclohexylbutyllithium, and the like.

The polymerization process of this invention can be carried out at any temperature within the range of about -80 to 150 C., but it is preferred to operate in the range of -20 to 80 C. The polymerization reaction can be carried out under autogenous pressures. It is usually desirable to operate at pressures sufficient to maintain the monomeric material substantially in the liquid phase. The pressure will thus depend upon the particular material being polymerized, the solvent mixture being employed, and the temperature at which the polymerization is carried out. However, higher pressures can be employed if desired, these pressures being obtained by some such suitable method as the pressurization of the reactor with a gas which is inert with respect to the polymerization reaction.

The amount of the organolithium compound which is employed in the polymerization of the conjugated dienes can vary over a Wide range. In general, the amount should be at least 0.02 part per 100 parts of the monomer to be polymerized, both amounts being on a weight basis. It is usually preferred to utilize an amount in the range of 0.02 to 2 parts by weight of the organolithium compound by 100 parts by weight of the total monomer charge. The upper limit for the amount of the organolithium compound to be employed depends largely upon the desired inherent viscosity of the polymer obtained in the polymerization. The inherent viscosity of the polymer produce decreases with increasing amounts of the organolithium catalyst. For example, in the case of butyllithium, a desirable catalyst level is from 0.15 to 0.20 part by weight of organolithium per 100 parts by weight of the conjugated diene charged to the reaction zone. It has been found that such a catalyst level produces a polymer having an inherent viscosity of from 2.0 to 2.25. A polymer of such an inherent viscosity has been determined to have a Mooney viscosity (ML-4) of approximately 25 to 35, a very desirable Mooney viscosity range.

As previously indicated, the process of this invention is concerned with production of rubbery polymers of conjugated dienes. The term rubbery polymer includes elastomeric, vulcanizable polymeric material which after vulcanization, i.e., crosslinking, possesses the properties normally associated with vulcanized rubber including materials which when compounded and cured exhibit reversible extensibility at 80 F. of over 100 percent of a specimens original length with a retraction of at least 90 percent within 1 minute after release of the stress necessary to elongate to 100 percent. The rubbery polymers produced in accordance with this invention are linear, soluble polymers. With regard to the solubility of the rubbery polymers of this invention, it is preferred that they con tain less than 50 percent gel as determined by the standard gel determination test. Actually, it has been found that polymers produced in accordance with the instant process generally contain no gel or substantially no gel.

The process of this invention can be carried out as a batch process by charging the monomeric material into a reactor containing the organolithium catalyst and the solvent mixture. The process can also be carried out continuously by maintaining the above-mentioned concentrations of reactants in the reactor for a suitable residence time. The residence time in a continuous process will, of course, vary within rather wide limits depending upon such variables as reaction temperature, pressure, the amount of catalyst used, and a monomeric material which is being polymerized. In a continuous process, the residence time generally falls within the range of 1 second to 1 hour when conditions within the specified ranges are employed. When a batch process is being utilized, the

4 time for the reaction can be as high as 24 hours or more although it is generally less than 24 hours.

Various materials are known to be destructive to the organolithium catalyst of this invention. These materials include carbon dioxide, oxygen, water, alcohols, mercaptans, and primary and secondary amines. It is highly desirable, therefore, that the monomers be freed of these materials, as well as other materials which tend to inactivate the catalyst. Any of the known means for removing such contaminants can be used. Also, it is preferred that the solvent mixture used in the process be substantially free of impurities such as water, oxygen and the like. In this connection, it is desirable to re move air and moisture from the reaction vessel in which the polymerization is carried out. Although it is preferred to carry out thepolymerization under anhydrous or substantially anhydrous conditions, it is to be understood that some water can be tolerated in the reaction mixture. However, the amount of water which may be tolerated in the mixture is insufficient to completely deactivate the catalyst.

At the completion of the polymerization reaction, when a batch process is used, the total reaction mixture is then treated to inactivate the catalyst by adding a catalystinactivatin'g material such as water, an alcohol, e.g., ethyl alcohol or isopropyl alcohol, an organic or inorganic acid, or the like. It is generally preferred to add only an amount of the catalyst inactivating material which is su'fiicient to deactivate the catalyst without causing precipitation of the dissolved polymer. It has also been found to be advantageous to add an antioxidant, such as phenylbeta-naphthylamine, to the polymer solution prior to precipitation of the polymer. After addition of the catalyst deactivating agent and the antioxidant, the polymer present in the solution can then be precipitated by the addition of an excess of a material such as ethyl alcohol or isopropyl alcohol. It is to be understood that deactivation of the catalyst and precipitation of the polymer can be accomplished in a single step. The precipitated polymer can then be recovered by filtration, decantation, or the like. In order to further purify the rubbery polymer, the separated polymer can be redissolved in a suitable solvent and then again precipitated by the addition of an alcohol. Thereafter, the polymer is again recovered by a suitable separation means, as indicated hereinbefore, and then dried. Any suitable hydrocarbon solvent can be used in this purification step to redissolve the polymer. When the process of the invention is carried out continuously, the total effluent from the reactor is pumped from the reactor to a catalyst-inactivating zone wherein the reactor effluent is contacted with a suitable catalyst-inactivating material, such as an alcohol. When an alcohol is used as the catalyst-inactivating material, it can also function to precipitate the polymer. In the event other catalyst-inactivating materials are employed which do not perform this dual rule, it is also necessary to add a suitable material, such as an alcohol, to precipitate the polymer. After separation from the solvent mixture and alcohol by filtration or other suitable means, the polymer is dried. The rubbery polymer can also be redissolved in a suitable diluent and again precipitated, as described above, in order to purify the material. The solvent mixture and alcohol can in all cases be separated, for example by fractional distillation, and reused in the process. As hereinbefore mentioned, it is within the scope of the invention to utilize an antioxidant in the process to prevent oxidation of the rubbery polymer. The antioxidant can be added to the reaction mixture prior to precipitation of the polymer, to the solution of redissolved polymer or to the solvent in which the polymer is to be subsequently redissolved.

The rubbery polymers which result when a monomeric material comprising a conjugated diene is polymerized by the method of this invention can be compounded by any of the known methods such as have been used in dry, nitrogen-filled bottle.

appropriate amount of dried reaction solvent.

the past for compounding natural rubber; Vulcanization accelerators, reinforcing agents, and fillers such as have been employed in natural rubber can likewise be used in compounding the polymers of this invention.

A more comprehensive understanding of the invention can be obtained by referring to the following illustrative examples which are not intended, however, to be unduly lirnitative of the invention. 1

Example 1 Several runs were made in which 1,3-butadiene was polymerized to a rubbery polymer using n-butyllithium as the polymerization catalyst.

The n-buty-llithium solutions used in these runs were prepared in the [following manner. A 1000 milliliter 3- 'necked flask, fitted with a reflux condenser, -a dropping funnel with a gas outlet side arm, and a high speed stirrer, wasswept with prepurified nitrogen and charged with 200 milliliters of dry, olefin-tree petroleum ether and 3.8 grams of lithium wire which had been out into lengths of about 0.5 centimeter. The dropping funnel was then attached, and a solution of 23 grams of 1-ehlorobutane in 100 milliliters of petroleum ether was charge-d to the dropping funnel. The stirrer was then started and brought to a high speed, and without cooling about 'to milliliters of the chlorobutane solution was added :in one portion. After the reaction had started, as evi- Parts by Weight Butadiene 100 100 Benzene 440 n-Butyllithium 0. 32 0. 32-0. 64 Diethyl ether- 0-80 357 Temperature, 50 50 Time, hours... 4 4

The results of the several runs, including the results of an infrared analysis of the polymer products, are shown hereinbelow in Table I.

TABLE I Butyllithium Configuration, Percent 1 Diethyl Conversion, Inherent Unsat, Run No. Recipe Ether, Percent Viscosity Percent 4 Parts by Milli- Parts by Cis Trans Vinyl Wt. moles Wt.

1 Method used in infrared examination was essentially the same as that set forth in The Analysis of Natural and Synthetic Rubbers by Infrared Spectroscopy, H. L. Dinsmore and D. C. Smith in Naval Research Laboratory Report No. P-2861, August denced by the evolution of heat, a cooling bath was placed 7 around the flask, and the remainder of the chlorobutane solution was added at the rate of 1 to 2 milliliters per minute. The addition of the chlorobutane solution was accomplished with very vigorous stirring. After the addition was completed, stirring and cooling was continued for from 30 to 45 minutes. The contents of the flask were then transferred to a container by .a suitable suction arrangement through inch stainless steel tubing. The container was then centrifuged and the supernatant n-butyllithiurn solution was carefully pressured into a Analysis showed the solution to be about 0.47 molar with respect to butyllithium.

The polymerization runs were conducted in 7 and 12- ounce beverage bottles which were first charged with the Prepurified nitrogen was dispersedthrough a fritted glass tube and bubbled through the solvent at the rate of 3 liters per minute for from 3 to ZOminutes. For 10* to 20 gram monomer charges the bottles were first capped with rubber "gaskets and metalcaps, and the monomer and butyllithium were introduced in that order by means of a syringe. Larger monomer charges were weighed in before the capping operation. The charged bottles were The polymers produced in the above runs contained no gel. While all of the polymerizations were carried out for 'four hours, it was noted that the runs containing ether polymerized rnuch faster-than the run in which the hydrocarbon alone was used as the solvent.

Example II Another series of runs was carried out in which essentially the same procedure was employed as described hereinabove in Example I. In these runs, however, triethyla-mine was employed as the polar compound instead of diethyl etherland the hydrocarbon used in the solvent mixture was cyclohexane.

The polymerization recipe employed in the runs of this example was as follows:

Parts by weight, C 'Butadiene Cyclohexane 390 ,N-Butyl'lithium 0.32 Triethylamine 0-80 Temperature, C. 50 Time, hours 16 The results of these runs, including the results of the infrared analysis of the polymer products, are set forth hereinbelow in Table II.

TAB LE II Triethyl- Unsatu- Configuration, percent 1 Run No. Recipe amine, Conversion, Inherent ration,

phm. percent Viscosity percent Ois Trans Vinyl 2 See note under Table I.

Example III A number of polymerization runs were carried out in which 1,3-butadiene was polymerized to a rubbery poly mer in the presence of n-butyllithium, prepared as described in Example I. These polymerization runs were carried out according to the procedure of Example I and In each of these runs, the various reactants were charged to the polymerization bottle in the order: cyclohexane, butadiene, polar compound and n-butyllithium. Two different polar compounds were employed, namely tetrahydrofuran and 1,2-dimethoxyethane. In the runs employing tetrahydrofur-an, the tetrahydrofuran was charged as a 1% by volume solution in cyclohexane.

The results of these runs are shown below in Table III.

1,3-but-adiene which comprises contacting a monomer consisting essentially of 1,3-butadiene with a catalyst consisting essentially of at least 0.02 part by weight per 100 parts by weight of said 1,3-butadiene of an organolithium compound corresponding to the formula RLi, wherein R is a radical selected from the group consisting of alkyl, aryl, cycloalkyl, ar-alkyl, alkaryl, alkylcycloalkyl, and cycloalkyl akyl, said contacting occurring in the range of 80 to 150 C. and in the presence of a solvent mixture, inert and liquid under conditions of the process, said solvent mixture consisting essentially of (1) a hydrocarbon selected from the group consisting of aromatic, paraffinic and cycloparaffinic hydrocarbons and (2) a polar compound selected from the group consisting of ethers, thioethers and tertiary amines, the amount of said polar compound in said mixture being in the range of 0.005 to weight percent of the total mixture; and recovering a rubbery homopolymer of said 1,3-butadiene.

2. The process according to claim 1 in which the amount of said organolithium compound is in the range of 0.02 to 2.0 parts by weight per 100 parts by weight of said 1,3-butadiene.

3. The process according to claim 1 in which said organolithium compound is 'butyllithium and the amount of said butyllithium is in the range of 0.15 to 0.20 part TABLE III Parts by Polymeri- Con- Configuration 1 Run Polar Compound Wt. Polar zation version, Number Employed Compound Time, Percent Hours Ois Trans Vnyl Tetrah drofuran 0. 1 0. 5 54 '35 51. 2 13. 8 y 0. 2 20 100 32.1 47. 7 20. 2 0.5 20 100 28. 1 44.1 27. 8 1 72 100 15 30 55 5 72 100 15 20 15 72 100 15 10 75 25 72 100 6 9 l. 0 20 100 Not determined 0. 5 20 100 Not determined 0. 2 20 100 15. 6 61. 8 0. 2 1. 5 76 10. 4 14. 8 74. 8 25 1. 5 93 11. 7 11. 9 76. 4 25 1. 5 95 8. 3 8. 3 83. 4

1 See note under Table I. 2 Polymerization temperature 30 0. 3 Polymerization temperature 5 C.

From the data set forth in Tables I, II and III hereinabove, it is seen that the ratio of cis-1,4 linkages to vinyl linkages can be controlled by varying the amount of the polar compound contained in the solvent mixture.

The rubbery polymers produced in accordance with this invention have utility in applications where natural and synthetic rubbers are used. For example, they can be used in the manufacture of automobile tires, gaskets, and other rubber articles. The polymers are also useful in applications requiring polymers of low ash content, and they can be used as an electrical insulating material.

As will be evident to those skilled in the art, many variations and modifications can be practiced upon consideration of the foregoing disclosure. Such variations and modifications are believed to be within the spirit and scope of the invention.

I claim:

1. A process for preparing a rubbery homopolymer of by weight per parts by weight of said 1,3-butadiene.

4. A process for preparing rubbery homopolymers of 1,3-butadiene having a desired ratio of cis 1,4-linkages to vinyl linkages which comprises contacting a monomer consisting essentially of 1,3-butadiene with a catalyst consisting essentially of at least 0.02 part by weight per 100 parts by weight of said 1,3-butadiene of an organolithium compound corresponding to the formula RLi, wherein R is a radical selected from the group consisting of alkyl, aryl, cyclo alkyl, aralkyl, alkaryl, alkylcycloalkyl and cycloalkylalkyl, said cont-acting occurring at a temperature in the range of -80 to C. and in the presence of a solvent mixture, inert and liquid under conditions of the process, said solvent mixture consisting essentially of (1) a hydrocarbon selected from the group consisting of aromatic, paraflinic and cyclopar-afiinic hydrocarbons, and (2) a polar compound selected from the group consisting of ethers, thioethers and tertiary amines, the

amount of said polar compound in said mixture being in the range of 0.005 to50 weight percent of the total mixture; adjusting the amount of said polar compound in said mixture so as to obtain a polymer product having a desired ratio of cis 1,4-linkages to vinyl linkages; and recovering the rubbery homopolymer of said 1,3-butadiene so produced.

I A process for preparing a rubbery homopolymer of 1,3-butadiene having a desired ratio of cis 1,4-linkages to vinyl linkages which comprises contacting said butadiene with a catalyst consisting essentially of in the range of 0.15 to 0.20 part by weight per 100 parts by weight of butadiene of n-butyllithium, said cont-actingoccurring at a temperature in the range of -80 to 150 C. and in the presence of a solvent mixture, inert and liquid under conditions of the process, said solvent mixture consisting essentially of cyclohexane and diox-ane, the amount of dioxane in said mixture being in the range of 0.005 to 50 weight percent of the tot-a1 mixture; adjusting the amount of dioxane in said solvent mixture so as to obtain a polymer product having a desired natio of cis l,-4-linkages to vinyl linkages; and recovering the rubbery homopolymer of butadiene so produced.

6. A process for preparing rubbery homopolymers of conjugated dienes which comprises contacting a monomer consisting essentially of an aliphatic conjugated diene containing from 4 to 10, inclusive, carbon atoms per molecule with a catalyst consisting essentially of at least 0.02 part by weight per 100 parts by Weight of said conjugated diene of an organolithium compound corresponding to the formula RLi, wherein R is a radical selected from the group consisting of alkyl, aryl, cycloalkyl, aralkyl, alkaryl, alkylcyoloalkyl, and cycloalkylalkyl, said contacting occurring in the range of -80 to 150 C. and in the presence of a solvent mixture, inert and liquid under conditions of the process, said solvent mixture consisting essentialy of benzene and diethyl ether, the amount of said diethyl ether in said mixture being in the range of 0.005 to 50 Weight percent of the total mixture; and recovering a rubbery homopolymer of said conjugated diene.

7. A process for preparing rubbery homopolymers of conjugated dienes which comprises contacting a monomer consisting essentially of an aliphatic conjugated diene containing from 4 to 10, inclusive, carbon atoms per molecule with a catalyst consisting essentially of at least 0.02 part by weight per 100 parts by weight of said conjugated diene of an onganolithium compound corresponding to the formula RLi, wherein R is a radical selected from the group consisting of alkyl, aryl, cyoloalkyl, aralkyl, alkaryl, alkylcyoloallkyl, and cycloalkylalkyl, said contacting occurring in the range of -80 to 150 C. and in the presence of a solvent mixture, inert and liquid under conditions of the process, said solvent mixture consisting essentially or" cyolohexane and diethyl ether, the amount of said diethyl ether in said mixture being in the range of 0.005 to 50 weight percent of the total mixture; and recovering a rubbery homopolymer of said conjugated diene.

8. A process for preparing rubbery homopolymers of conjugated dienes which comprises contacting a monomer consisting essentially of an aliphatic conjugated diene containing from 4 to 10, inclusive, carbon atoms per molecule with a catalyst consisting essentially of at least 0.02 part by weight per 100 parts by Weight of said conjugated diene of an organolithium compound corresponding to the formula RLi, wherein R is a radical selected from the group consisting of alkyl, aryl, cyoloalkyl, aralkyl,, alkaryl, alkylcycloalkyl, and cycloalkylalkyl, said contacting occurring in the range of -80 to 150 C. and 1n the presence of a solvent mixture, inert and liquid under conditions of the process, said solvent mixture consisting essentially of cyolohexane and triethylamme, the amount of said triethylamine in said mixture being 1n the range of 0.005 to 50 weight percent of the total mixture; and

10 "recovering a rubbery homopolymer of said conjugated diene.

9. A process for preparing rubbery homopolymers of conjugated dienes which comprises contacting a monomer "consisting essentially of an aliphatic conjugated diene containing from 4 to 10, inclusive, carbon atoms per molecule with a catalyst consisting essentially of at least 0.02 part by weight per 100 parts by weight of said conjugated diene of anoriganolithium compound corresponding to the [formula RLi, wherein R is a radical selected from the group consisting of alkyl, aryl,cycloalkyl, aralkyl, alkaryl, alkylcycloalkyl, and cycloalkylalkyl, said contacting occurring in the rangeof to 150 C. and in the presence of a solvent mixture, inert and liquid under conditions of the process, said solvent mixture consisting essentially of cyolohexane and 1,2-dimethoxyethane, the amount of said dimethoxyebhane in said mixture being in the range of 0.005 to 50 weight percent of the total mixture; and recovering a rubbery homopolymer of said conjugated diene.

10. A process -for preparing rubbery homopolymers of conjugated dienes which comprises contacting a monomer consisting essentially of an aliphatic conjugated diene containing from 4 \to 10, inclusive, carbon atoms per molecule with a catalyst consisting essentially of at least 0.02 part by weight per parts by weight of said conjugated diene of an organolithium compound corresponding to the formula RLi, wherein R is a radical selected from the group consisting of alkyl, aryl, cycloalkyl, aralkyl, alkaryl, alky lcycloalkyl, and cycloalkylalkyl, said contacting occurring in the range of -80 to C. and in the presence of a solvent mixture, inert and liquid under conditions of the process, said solvent mixture consisting essentially of cyclohexane and tetrahydrofuran, the amount of said tetrahydrofuran in said mixture .being in the range of 0.005 to 50 weight percent of the total mixture; and recovering a rubbery homopolymer of said conjugated diene.

11. A process for preparing a block polymer by catalytic polymerization which comprises polymerizing a monomer consisting essentially of an aliphatic conjugated diene containing [from 4 to 10, inclusive, carbon atoms per molecule with a catalyst consisting essentially of at least 0.02 part by weight per 100 parts by weight of said conjugated diene of an organolithium compound corresponding to the formula RLi, wherein R is a radical selected from the group consisting of alkyl, aryl, cycloalkyl, aralkyl, alkaryl, alkylcycloalkyl and cyoloalkylalkyl, said contacting occurring at a temperature in the range of -80 to 150 C. and in rthe presence of a solvent, inert and liquid under conditions of the process, said solvent consisting essentially of a hydrocarbon selected from the group consisting of aromatic, parafiinic and cycloparaflinic hydrocarbons; while said polymerization is proceeding, adding a polar compound to said hydrocarbon solvent in an amount to provide a mixture containing in the range of 0.005 to 50 weight percent of said polar compound, said polar compound being selected from the group consisting of ethers, thioethers and tertiary amines; allowing said polymerization to proceed in the presence of said hydrocarbon solvent and said polar compound; and recovering the block poly-mer so produced.

12. The process for preparing a block homopolymer of a 1,3 diene which comprises polymerizing 1,3 diene with a catalyst consisting of a lithium hydrocarbon in a hydrocarbon solvent selected from aromatic, paraflinic, and cycloparaffinic hydrocarbons and then vn'thout inactivating the organolithium catalyst polymerizing the resultant polymer with additional 1,3 diene monomer in a solvent system consisting of said hydrocarbon solvent plus 0.005 to 50 weight percent of an organic compound selected from the group consisting of others, thioethers and tertiary amines and in the absence of additional lithium hydrocarbon.

1 1 13. The process of claim 12 in which the diene is 1,3- butadiene.

14. The process of claim 13 in which the lithium hydrocarbon is n-butyllithimm.

15. The process of claim 14 in which the organic com- 5 pound is tetrahydrofuran.

16. The process of claim 12 in which the monomer is isoprene.

17. A block homopo'lymer Off a 1,3 diene as prepared by the process of claim 12.

18. A block homopolymer of isoprene as prepared by the process of claim 12.

19. A block homopolymer of butadiene as prepared by the process of claim 12.

References Cited by the Examiner UNITED STATES PATENTS 7/1964 Kuntz .26094.2.

OTHER REFERENCES JOSEPH L. SOHOFER, Primary Examiner.

C. R. REAP, H. WONG, Assistant Examiners. 

1. A PROCESS FOR PREPARING A RUBBERY HOMOPOLYMER OF 1,3-BUTADIENE WHICH COMPRISES CONTACTING A MONOMER CONSISTING ESSENTIALLY OF 1,3-BUTADIENE WITH A CATALYST CONSISTING ESSENTIALLY OF AT LEAST 0.02 PART BY WEIGHT PER 100 PARTS BY WEIGHT OF SAID 1,3-BUTADIENE OF AN ORGANOLITHIUM COMPOUND CORRESPONDING TO THE FORMULA RLI, WHEREIN R IS A RADICAL SELECTED FROM THE GROUP CONSISTING OF ALKYL, ARYL, CYCLOALKYL, ARALKYL, ALKARYL, ALKYLCYCLOAKLYL, AND CYCLOALKYLAKYL, SAID CONTACTING OCCURRING IN THE RANGE OF -80* TO 150*C. AND IN THE PRESENCE OF A SOLVENT MIXTURE, INERT AND LIQUID UNDER CONDITIONS OF THE PROCESS, SAID SOLVENT MIXTURE CONSISTING ESSENTIALLY OF (1) A HYDROCARBON SELECTED FROM THE GROUP CONSISTING OF AROMATIC, PARAFFINIC AND CYCLOPARAFFINIC HYDROCARBONS AND (2) A POLAR COMPOUND SELECTED FROM THE GROUP CONSISTING OF ETHERS, THIOETHERS AND TERTIARY AMINES, THE AMOUNT OF SAID POLAR COMPOUND IN SAID MIXTURE BEING IN THE RANGE OF 0.005 TO 50 WEIGHT PERCENT OF THE TOTAL MIXTURE; AND RECOVERING A RUBBERY HOMOPOLYMER OF SAID 1,3-BUTADIENE.
 11. A PROCESS FOR PREPARING A BLOCK POLYMER BY CATALYTIC POLYMERIZATION WHICH COMPRISES POLYMERIZING A MONOMER CONSISTING ESSENTILALLY OF AN ALIPHATIC CONJUGATED DIENE CONTAINING FROM 4 TO 10, INCLUSIVE, CARBON ATOMS PER MOLECULE WITH A CATALYST CONSISTING ESSENTIALLY OF AT LEAST 0.02 PART BY WEIGHT PER 100 PARTS BY WEIGHT OF SAID CONJUGATED DIENE OF AN ORGANOLITHIUM COMPOUND CORRESPONDING TO THE FORMULA RLI, WHEREIN R IS A RADIACL SELECTED FROM THE GROUP CONSISTING OF ALKYL, ARYL, CYCLOALKYL, ARALKYL, ALKARYL, ALKYLCYCLOALKYL AND CYCLOALKYLALKYL, SAID CONTACTING OCCURRING AT A TEMPERATURE IN THE RANGE OF -80 TO 150*C. AND IN THE PRESENCE OF A SOLVENT, INERT AND LIQUID UNDER CONDITION SOF THE PROCESS, SAID SOLVENT CONSISTING ESSENTIALLY OF A HYDROCARBON SELECTED FROM THE GROUP CONSISTING OF AROMATIC, PARAFFINIC AND CYCLOPARAFFINIC HYDROCARBONS; WHILE SAID POLYMERIZATION IS PROCEDDING, ADDING A POLAR COMPOUND TO SAID HYDROCARBON SOLVENT IN AN AMOUNT TO PROVIDE A MIXTURE CONTAINING IN THE RANGE OF 0.005 TO 50 WEIGHT PERCENT OF SAID POLAR COMPOUND, SAID POLAR COMPOUND BEING SELECTED FROM THE GROUP CONSISTING OF ETHERS, THIOETHERS AND TERTIARY AMINES; ALLOWING SAID POLYMERIZATIONTO PROCEED IN THE PRESENCE OF SAID HYDROCARBON SOLVENT AND SAID POLAR COMPOUND; AND RECOVERING THE BLOCK POLYMER SO PRODUCED. 